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Re: Digital file sizes and storage



Charles,

IF:

FS=file size, SH=Source Height, SW=Source Width, BD=Bit Depth, dpi=dots PER
INCH, and /8 because 8 bits = 1 byte,

THEN:

FS = (SH x SW x BD x {dpi x dpi})/8

so... (10 x 8 x 8 x {600x600})/8 = FS = 28800000 bytes or 28.8 MB

But that's just the math...the hard answer  is the rest of your question and
there are other variable in there that can compound the answer.

What is the MAXIMUM optical resolution of your scanning device? This will
represent the absolute maximum resolution you can achieve for
non-interpolated scans, something you need to know before creating
"archival" scanned files. Why 8-bit grayscale? Are these vintage B&W photos
tha may actually contain some "color" tone to them? That information would
be forever lost if you did 8-bit grayscale...

Given the printing technology available today, does 600 dpi yield enough
information in print format? Might want to go higher...

Just some thoughts on one of those rare, gorgeous Friday afternoons in
Houston that finds me down here in the basement, on-line.

Dennis Moser, MILS, Web Librarian
John P. McGovern Historical Collections and Research Center
Houston Academy of Medicine-Texas Medical Center Library
1133 M. D. Anderson Blvd, Houston, TX 77030-2809
dennism@library.tmc.edu
"That so few now dare to be eccentric,
marks the chief danger of the time."
~~~ John Stuart Mill


-----Original Message-----
From: Charles Greifenstein <greifenstein@COLLPHYPHIL.ORG>
To: ARCHIVES@LISTSERV.MUOHIO.EDU <ARCHIVES@LISTSERV.MUOHIO.EDU>
Date: Friday, March 17, 2000 11:55 AM
Subject: Digital file sizes and storage


>I need some advice on determining file sizes of digital images.  Is there a
>formula for determining file size?  What would be the file size of an 8" x
>10" black and white photograph scanned at 8-bit grayscale at 600 dpi and
>stored as an uncompressed TIFF file?
>Also, what would be an acceptable dpi for an "archival" image--i.e., one
>that would be for in-house use and that would be publishable in printed
>form.  300 dpi?  600 dpi?
>
>Thanks for your help
>
>
>Charles B. Greifenstein
>Curator of Archives & Manuscripts
>College of Physicians of Philadelphia
>19 South 22nd Street
>Philadelphia, PA  19103-3097
>(215) 563-3737 ext. 275
>Fax (215) 569-0356
>greifenstein@collphyphil.org
>
>A posting from the Archives & Archivists LISTSERV List!
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>

A posting from the Archives & Archivists LISTSERV List!

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      In body of message:  SUB ARCHIVES firstname lastname
                    *or*:  UNSUB ARCHIVES
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Or to do *anything* (and enjoy doing it!), use the web interface at
     http://listserv.muohio.edu/archives/archives.html

Problems?  Send e-mail to Robert F Schmidt <rschmidt@lib.muohio.edu>